Concatenate non zero digits and multiply by sum i

Math

55.7% acceptance

Feb 25, 2026

You are given an integer n. Form a new integer x by concatenating all the non-zero digits of n in their original order. If there are no non-zero digits, x = 0. Let sum be the sum of digits in x. Return an integer representing the value of x * sum.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn sum_and_multiply(n: i32) -> i64 {
    let digits: Vec<i64> = n.to_string().bytes()
      .map(|b| (b - b'0') as i64)
      .filter(|&d| d != 0)
      .collect();
    if digits.is_empty() { return 0; }
    let x: i64 = digits.iter().fold(0i64, |acc, &d| acc * 10 + d);
    let sum: i64 = digits.iter().sum();
    x * sum
  }
}